huh.
well, i doubt it is D. it is not necessarily because of the pairing that protein copies are made.
A could be referring to the 5 carbon sugar forming the helix of the DNA, but again i fail to see why the pairing itself has an affect on it.
i would argue that B is correct because like i said above a-->t only so using half the DNA strand and attaching a pair would provide a concrete method. it would be like so: 0-->1, 1-->0
0100110
1011001
you could use one line or the other to pair it with a matching value and end up with the same pair, if that makes sense.